Let me prefix this by saying that this is my first experiment with 900Mhz equipment, up until now I have extensively used 2.4Ghz and 5.8Ghz in a full range of Mikrotik, Ubiquity and Senao products.

The main question I have is that I would like some sort of confirmation or negation by experienced users:

Is it, as I've heard/read, a BAD idea to put an SR9 card into the same enclosure as an operating 2.4Ghz card?

Is the same true for 5.8Ghz?

Right now I am experimenting with my SR9's on RB411H boards, but I am thinking about moving the antenna and radio to another board on the tower side so that I can reduce tower clutter. Obviously, I don't want to cause any interference with existing radios.

Another thing I'm curious about is signal levels. With a noise floor of -98dB, should -86dB signal be enough for a reliable connection? According to radio mobile, the link is good:
and indicates that I'm 9dB over the 99.8% reliability margin:
See 3rd attached image for link tool details.

Predicted signal is -82dB, but I'm losing an additional ~4dB due to foliage (it was expected). At the moment, one of my cards has a weak transmitter and is being received at only -93dB, so I can't tell if it's going to be stable through experimentation - plus, I'd like feedback from experienced 900Mhz users.

Thanks in advance!

I've found that if the signal isn't into the low 70's, you'll have issues.

Cell phones interfere, power company in AL, dunno what they use in Kansas.

With 2.4, I like my customers in the -70's, but I'll let a low -80 slide if its the best I can get. On 900MHz, the noise floor hits -80s quite often here. I'm going to install a cavity filter next time I go up and see how that works out, but even when the noise isn't that bad, 900MHz just doesn't work as well as I though it would.

Thanks for the reply

I've found that if the signal isn't into the low 70's, you'll have issues.

I hope that's not the case, but I'll just have to find out. I have a few options though, as I can move the 30M side up to about 35M if I really have to, but that moves the Fresnel >1.0 ... but I'm not sure it will matter, because I have lots of trees on the client side to deal with. Basically I have to blow right through the canopy for about 2 blocks.

Regardless, I don't think I'm going to be able to get better than about an -85 signal.

Cell phones interfere, power company in AL, dunno what they use in Kansas.

900Mhz cell phones are going the way of the dodo bird here.
Our power company is Westar Energy

With 2.4, I like my customers in the -70's, but I'll let a low -80 slide if its the best I can get. On 900MHz, the noise floor hits -80s quite often here. I'm going to install a cavity filter next time I go up and see how that works out, but even when the noise isn't that bad, 900MHz just doesn't work as well as I though it would.

I'm showing a noise floor of about -98 or so on the 900Mhz - which I found very impressive. I have heard so many reports of terrible noise floors on 900Mhz, I was expecting it to be MUCH worse. Maybe I'm getting a good noise floor in relation to what others get because this is a point to point connection with 13dBi Yagi's. Regardless, I should be able to get an SNR of >=10dB.

My goal is to disconnect my cable modem connection so I can save money, and be back on my own network. It wounded my soul when I moved and couldn't get my own DSL or 2.4Ghz wireless

I know this thread is a little old, but I figured I'd throw a few things in here.

I don't know if you can still get them as I haven't ordered one in awhile, but an 18dbi yagi would give you about 10db overall gain which would put the link into a much more stable range. http://www.wifi-parts.com/90ya18.html

I don't setup any customer without -82 or better signal. -85 usually works, but doesn't give you much overhead. -88 is about the cutoff before things usually quit working. I've seen it hold on as far as -92.

Keep in mind that EIRP on 900mhz is 36 regardless of PtP or PtMP. You would have to run the radio at 18dBm to stay legal with those yagi's.

Using 5mhz channels should also increase your signal by 6db over 20mhz channels.

Agreed, but in my situation, I got a weaker but more stable signal at 10MHz. Also seems some change made around 3.15 improved my XR9's stability.

I have found SR9 to be more susceptible to interference and finicky than 900mhz systems like Trango or Alvarion. We tried two links with it, and gave up in favor of Trango and Alvarion.

If you have LOS, you should use a higher frequency.

900 is highly susceptible to variable service for a variety of reasons. Obstacles and trees close to the antenna affect 900 much more than LOS based radio systems, (as we'd avoid shooting through obstacles or trees with those.) The signal carriers further and there is less spectrum too, meaning more noise to contend with. Some of the stuff works well, but it doesn't have the performance or low cost of higher frequency gear.

I'd recommend giving the XR9 or SR9 another chance. My XR9 customer (just one due to previous issues) was dropping regularly, and at 8:30, 12:30 and 5:30 every day with older versions of ROS.

Since the update, 900MHz has become the rock, uptimes pretty much match the uptimes for my backhaul, which only goes down when I make changes to the system. I am going to start deploying 900MHz as soon as time permits.

I use a 900Mhz PtP link for my office to my own network.
133c, SR9, WDS, 1Km through dense trees.
I run it in B only, 10Mhz channel.
Noise is at -98, signal -81.
Runs consistently at 2Mbps.
Try to get signal above noise as close to minimum of 20 db as possible and you'll be fine.
A 411/XR9 running on 3.13 will work even better.